Submission #992651

#	Time	Username	Problem	Language	Result	Execution time	Memory
992651		kkzyr	Global Warming (CEOI18_glo)	C++17	0 / 100	84 ms	6260 KiB

glo

#include <iostream>
#include <set>
using namespace std;

int n, x;
int nums[200001];
int flipped_nums[200001];
int lis[200001];
int dp1[200001];
int dp2[200001];

const int INF = 1e9 + 5;

int binary_search(int key){
    int lo = 1;
    int hi = n;
    int ans = 0;
    while (lo <= hi){
        int mid = (lo + hi)/2;
        if (lis[mid] < key){
            ans = mid;
            lo = mid + 1;
        }
        else{
            hi = mid - 1;
        }
    }
    return ans;
}

int main(){
    cin >> n >> x;
    for (int i = 1;i <= n;i++){
        cin >> nums[i];
        flipped_nums[n - i + 1] = INF - nums[i];
    }
    int ans = 0;
    for (int j = 1;j <= n;j++){
        lis[j] = INF;
    }
    for (int j = 1;j <= n;j++) {
        int key = nums[j];
        int index = binary_search(key);
        lis[index + 1] = key;
        if (index + 1 > ans) {
            ans = index + 1;
        }
        dp1[j] = index + 1;
    }
    for (int j = 1;j <= n;j++){
        lis[j] = INF;
    }
    for (int j = 1;j <= n;j++) {
        int key = flipped_nums[j];
        int index = binary_search(key);
        lis[index + 1] = key;
        if (index + 1 > ans) {
            ans = index + 1;
        }
        dp2[j] = index + 1;
    }
    set<int> s;
    for (int i = 1;i <= n;i++){
        s.insert(dp2[i]);
    }
    for (int i = 1;i < n;i++){
        s.erase(dp2[i]);
        int sum = dp1[i] + *s.upper_bound(nums[i] - x);
        if (sum > ans){
            ans = sum;
        }
    }
    cout << ans << '\n';
    return 0;
}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 10
• Subtask 3: 0 / 13
• Subtask 4: 0 / 10
• Subtask 5: 0 / 20
• Subtask 6: 0 / 17
• Subtask 7: 0 / 25